Primary alcohols dehydrogenation/decarbonylation

While adsorbed primary alcohols on the Pd( 111) surface dehydrogenate sequentially to form the corresponding adsorbed aldehyde and acyl species prior to their decarbonylation (23), we have found no evidence for aldehyde formation from primary alcohols on Rh(l 11) (2124). Instead, alcohol and aldehyde decarbonylation pathways on Rh(lll) appear to be non-intersecting. This surprising divergence of reaction pathways for such closely related molecules is demonstrated by two critical observations ... 

The above reaction is reversible so that primary alcohols may be dehydrogenated to an aldehyde which could decarbonylate to produce CO. It has been shown that the 1-alcohol and corresponding aldehyde are at or near an equilibrium composition when using a doubly promoted iron catalyst at 7 atm. The CO produced by the above reaction could produce CO2 through the WGS reaction ... 

Several other primary alcohols could be converted in this manner into the corresponding alkanes and syngas. A mechanism was suggested, consisting of a decarbonylation and a dehydrogenation cycle, with a coordinatively unsaturated iridium complex as common intermediate (Scheme 3.21). 

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